This invention belongs generally to the field of apparatuses for the transport of fluids at controlled flow rates. More particularly, the invention pertains to flow-regulating pumps adapted to the handling of fluids which must be isolated from the surrounding environment either because the fluids are hazardous, or because contamination must be strictly avoided. Specifically, the invention is embodied in an apparatus for continuously administering fluid nutrients or medicaments internally to the human body, especially for the purpose of enteric feeding.
In medicine, the management of a variety of disorders or disabilities may at some point indicate the employment of enteric feeding. A common technique utilizes a nasogastric tube introduced through a nostril of the patient and extending from there into the stomach. Through this tube, a variety of easily digested fluid nutrients can be more-or-less continuously introduced into the stomach without requiring intervention by the patient, and without stress to the gastroenteric system of the patient. Consequently, the technique may often be employed for severely debilitated or comatose patients.
Because such patients are virtually unable to cope with malfunctions in the enteric feeding apparatus, and because constant supervision of the apparatus by a medical attendant is prohibitively expensive, a very high degree of reliability of the apparatus is essential if accidents are to be avoided. Moreover, the apparatus needs to be designed in such a way as to minimize daily expenses incurred through its use, since the period of time during which it is required may extend for months or even years. Finally, the apparatus must be as simple to use as possible, especially since attendants of very limited training may be required to use it, as when a patient is discharged from a medical or nursing facility to return home while continuing enteric feeding.
Chief among the malfunctions which must be avoided in an enteric feeding apparatus is the occurrence of a sudden inrush of the fluid nutrient, which could result in the filling of the esophagus, followed by the disastrous incursion of the fluid into the tracheo-pulmonary system. The consequences of such an inrush, such as pneumonia or suffocation, are obviously so serious that only exceptionally reliable, fail-safe designs can be considered.
Beyond the prevention of such a disastrous accident, the design of an enteric feeding apparatus should favor rapid and simple initial setup of the apparatus, and ease in changing the container bag. The flow rate of the fluid nutrient should be easy to establish and control, and long-term variations in the flow rate should not exceed .+-.15% without operator intervention.